BU9847GUL-W ROHM Co. Ltd., BU9847GUL-W Datasheet - Page 3

• Manufacturer Part Number: BU9847GUL-W
• Description: I 2 C Bus 4kbit 512?8bit Eeprom
• Manufacturer: ROHM Co. Ltd.

◇ NOTES FOR POWER SUPPLY
◇CAUTIONS ON USE
(1) Absolute maximum ratings
(2) GND electric potential
(3) Thermal design
(4) Terminal to terminal shortcircuit and wrong packaging
(5) Use in a strong electromagnetic field may cause malfunction, therefore, evaluated design sufficiently.
Vcc rises through the low voltage region in which internal circuit of IC and the controller are unstable, so that device
may not work properly due to an incomplete reset of internal circuit. To prevent this, the device has the feature of
P.O.R. and LVCC. In the case of power up, keep the following conditions to ensure functions of P.O.R. and LVCC.
1. It is necessary to be "SDA='H'" and "SCL='L' or 'H'".
2. Follow the recommended conditions of tR, tOFF, Vbot for the function of P.O.R. during power up.
3. Prevent SDA and SCL from being "High-Z".
Vcc
A） Unable to keep condition 1.
B） Unable to keep condition 2.
C） Unable to keep both conditions 1 and 2.
In case that condition 1. and/or 2. cannot be met,
take following actions.
If the absolute maximum ratings such as impressed voltage and action temperature range and so forth are
exceeded, LSI may be destructed. Do not impress voltage and temperature exceeding the absolute maximum
ratings. In the case of fear exceeding the absolute maximum ratings, take physical safety countermeasures such
as fuses, and see to it that conditions exceeding the absolute maximum ratings should not be impressed to LSI.
Set the voltage of GND terminal lowest at any action condition. Make sure that each terminal voltage is lower
than that of GND terminal.
In consideration of permissible loss in actual use condition, carry out heat design with sufficient margin.
When to package LSI onto a board, pay sufficient attention to LSI direction and displacement. Wrong packaging
may destruct LSI. And in the case of shortcircuit between LSI terminals and terminals and power source,
terminal and GND owing to foreign matter, LSI may be destructed.
0
( SDA is "LOW" during power up.)
→ Control SDA ,SCL to be "HIGH" as Fig.-3(a),
→ After power becomes stable, execute
→ Follow the instruction A first, then the instruction B.
Fig.-2
3(b).
software reset.
Vcc RISING WAVEFORM
tOFF
tR
Vbot
REV. A
◇RECOMMENDED CONDITIONS OF tR, tOFF, Vbot
After Vcc becomes stable
Below 100ms
Below 10ms
SDA
Fig.-3（a） SCL='H' and SDA='L'
Vcc
SCL
tR
Above 10ms
Above 10ms
tDH
tLOW
tOFF
tSU:DAT
After Vcc becomes stable
Fig.-3（b） SCL='L' and SDA='L'
Below 0.3V
Below 0.2V
Vbot
tSU:DAT
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